石墨烯/半导体异质结柔性光电探测器的应变调控与机理研究

Graphene has the highest carrier mobility, and is suitable for building graphene/ semiconductor heterostructure high sensitivity photodetectors by compound with semiconductor with excellent light absorbing performance. In addition, by utilizing external field to realize the property modulation is an important way to improve the performance of materials and devices. This project aims on the controllable synthesis and positioning shift of graphene, ZnO nanomatrials and MoS2 nanomaterials, and construct graphene /ZnO and graphene /MoS2 two kinds of flexible photodetectors by compound graphene with ZnO and MoS2 piezoelectric semiconductors. The systematic research about the photoelectric conversion and detection performance of the constructed devices will be carried out. The effect of size and structure of nanomaterials on the device properties will be investigated. The property comparison between photoconductive and photovoltaic photodetectors will be presented, and the device properties will be enhanced by the optimization of fabrication and design of structure. The modulation regulation of stress/ strain on the properties of photodetectors will be studied. The strain modulation method for the enhancement of device performance will be established. The modulation mechanism of stress/ strain on interface contact barrier and device property will be revealed by the comparison of experimental results and theoretical calculation. Combined the semiconductor band structure analysis and theoretical simulation, the modulation mechanism of strain induced piezoelectric potential on the photo-generated electron-hole pair generation, separation and transport at the device interface will be presented. Fast and high responsivity graphene/ semiconductor heterostructure photodetectors will be constructed, and the application of photodectectors in the fields of photo-communication and fast detection will be promoted.

具有高载流子迁移率的石墨烯，通过与光吸收性能优异的半导体复合可构建高灵敏度石墨烯/半导体异质结光电探测器，而外场是调控材料和器件性能的重要方式。本项目拟通过将石墨烯与ZnO和MoS2两种压电半导体复合构建石墨烯/ ZnO与石墨烯/MoS2两种异质结柔性光电探测器，并对构建器件的光电转换与探测性能开展系统研究。研究材料种类、尺寸与结构等对器件光电转换与探测性能的影响，对比分析光导型和光伏型光电探测器的性能，确定提升器件性能的制备工艺与器件结构。研究应力/应变对器件光电探测性能的调控规律，建立提升器件性能的应变调控方案。通过实验结果与理论计算对比，揭示应力/应变对界面接触势垒和器件性能的调控机制。结合能带结构分析与理论模拟，发现应变压电电势对器件界面处光生电子空穴对产生、分离和传输的调控规律。研制响应速度快、响应度高的石墨烯/半导体异质结光电探测器，推动其在光通讯、快速探测领域的应用。

光电探测器在国民经济和国防等领域均有广泛用途。石墨烯具有高载流子迁移率，通过与光吸收性能优异的低维半导体复合可构建高灵敏度石墨烯/半导体异质结光电探测器，而外场是调控材料和器件性能的重要方式。.本项目开展了二维石墨烯和MoS2、WSe2、ZnO等低维半导体材料的控制制备研究，发展了低维材料的无损转移方式，实现了高质量低维材料的可控制备与转移。建立了二维MoS2硫空位缺陷与电子浓度的有效调控策略，实现了MoS2半导体特性的有效调控。构筑了MoS2同质结自驱动柔性光电探测器，光响应度达308 mA/W。设计构筑了二维ZnO紫外光电探测器，在日盲型波段具有良好的光响应性能。设计构建了具有周期性应变的二维MoS2/一维ZnO阵列混合维度范德华异质结阵列，发现应变可提高界面电荷转移效率，使界面处MoS2的荧光淬灭度超过50%。构筑了二维石墨烯/一维氧化锌和二维WSe2/一维ZnO等多种混合维度异质结构柔性光电探测器，研究了应变对光电探测器的性能调控作用与机制。通过施加外应变，提高了器件的光电流和光响应度。石墨烯/ZnO阵列薄膜异质结构光电探测器在-0.0349%的压应变下，光响应度提高19%。石墨烯/ZnO纳米线异质结构光电探测器件在0.44%的拉伸应变下，光响应度提高了26%。提出并验证了光电探测器的应变调控机理，应变诱导的压电极化电荷能够调控异质结构界面处的电荷传输。ZnO在应变下产生的压电电势可有效调控界面载流子行为、提升器件性能。.通过研究，实现了多种低维材料形貌和结构的有效调控。提出了多种低维材料混合维度异质结柔性光电探测器的设计构筑方法，通过应变调控实现了器件光探测性能的大幅提升，阐明了应变压电势对器件光探测性能的调控机制。研究结果对推动低维材料在光电探测领域的应用具有重要意义。